Method for spinning staples by means of the open-end system

ABSTRACT

A method and an apparatus for spinning long staples or short staples is disclosed in which the exit end of the staple inlet guide tube is close to and opposite the upper inner wall of the spinning rotor and the inner wall extending from the abovementioned inner wall to the maximum diameter portion is shaped in a frustoconical form steeply tapered with respect to a horizontal plane at the maximum diameter portion. Staples from the staple inlet guide tube are sucked to deposit on the upper inner wall and slide gradually toward the maximum diameter portion. If desired, separation of long staples may be performed between the exit end of the staple inlet guide tube and the upper inner wall of the spinning rotor. A stationary cylindrical body is provided in the spinning rotor to stabilize the rotational air stream within the spinning rotor. The yarn outlet guide tube is positioned in said cylindrical body. Between the yarn outlet guide tube and the maximum portion is interposed a friction member. On the upstream side of the friction member there is given a false twist in the same direction as the actual twist given by the spinning rotor and on the downstream side at least a portion of the false twist is cleared.

United States Patent 191 Shino 1 Sept. 9, 1975 METHOD FOR SPINNING STAPLES BY MEANS OF THE OPEN-END SYSTEM Masakazu Shino, 3-13, Sanwa-cho, Yamatotakada, nara, Japan [22] Filed: Aug. 7, 1973 [2]] Appl. No.: 386,374

[76] Inventor:

Primary Examiner-John W. Huckert Assistant Examiner-Charles Gorenstein [57] ABSTRACT A method and an apparatus for spinning long staples or short staples is disclosed in which the exit end of the staple inlet guide tube is close to and opposite the upper inner wall of the spinning rotor and the inner wall extending from the above-mentioned inner wall to the maximum diameter portion is shaped in a frustoconical form steeply tapered with respect to a horizontal plane at the maximum diameter portion. Sta ples from the staple inlet guide tube are sucked to deposit on the upper inner wall and slide gradually toward the maximum diameter portion. If desired. separation of long staples may be performed between the exit end of the staple inlet guide tube and the upper inner wall of the spinning rotor. A stationary cylindrical body is provided in the spinning rotor to stabilize the rotational air stream within the spinning rotor. The yarn outlet guide tube is positioned in said cylindrical body. Between the yarn outlet guide tube and the maximum portion is interposed a friction member. On the upstream side of the friction member there is given a false twist in the same direction as the actual twist given by the spinning rotor and on the downstream side at least a portion of the false twist is cleared.

1 Claim. 8 Drawing Figures PATENTEU 9|975 3.903.683

SHEET 1 [IF 3 PATENTED EP 91915 SE'IKET 2 BF 3 FIG.3

PIC-3.7

METHOD FOR SPINNING STAPLES BY MEANS OF THE OPEN-END SYSTEM BRIEF SUMMARY OF THE INVENTION This invention relates to a method and an apparatus for spinning staples by means of the open-end system and, more particularly, to a spinning method and apparatus which enables the making of a fine count yarn from long staples as well as the separation of long staples within the spinning rotor.

In the prior art pen-end system it is possible to spin short staples but it is impossible to spin long staples into a fine count yarn efficiently. This is mainly because of frequent breaking of the yarn at the maximum inner diameter portion, i.e. the collecting portion of the spinning rotor. As is well known, the long staples collected at the collecting portion undergo a big centrifugal force and therefore the staple between the collecting portion and the end of the yarn outlet guide tube must be endowed with a sufficient tensile strength that it can be drawn out withstanding such a centrifugal force. To solve this, it has so far been tried to insert a friction member in the end of the yarn outlet guide tube for hard twisting the staples between the collecting portion and the end of the yarn outlet guide tube to increase the twisting of the staples thereby to prevent the yarn from breaking. Such a method has still been unsuccess ful in avoiding the breaking of yarn at the collecting portion and the manufacture of a fine count yarn from long staples has been impossible.

The inventors of the present invention have studied thoroughly on the causes of yarn breaking at the yarn grasping point of the collecting portion of a spinning rotor and have found the following facts.

Namely, in the prior art spinning method or apparatus, the staples from the inlet guide tube are dropped directly onto the collecting portion and these dropped staples overlie one another at the collecting portion, which will give rise to an intertwinement of staples at the moment they are taken away from the collecting portion, causing the breaking of yarn so that the spinning of long staples becomes impossible. Besides, in the prior art, the relative position of the collecting portion and the friction member placed in the end of the yarn outlet guide tube is not adequate enough to give sufficient twisting at the yarn grasping point.

Also there has so far been known the open end spinning method in which spun yarn is made by using the rotating air stream and centrifugal force due to rotation of a spinning rotor. In this method, it is necessary that the staples fed to the spinning rotor should be already separated into single individuals as by opening rollers, since in the prior art method, wherein the staples from the inlet guide tube are discharged directly onto the collecting portion or its nearby area of the spinning rotor, it is impossible to separate the staples in the spinning rotor.

Therefore, it is an object of the present invention to provide a spinning method and an apparatus therefor which enables efficient spinning of long staples,

lt is further object of the invention to provide a spinning method and an apparatus therefore which enables the separation of a few long staples in the spinning rotor that are not yet separated, and the gradual falling of the separated staples to the collecting portion while maintaining mutual parallelism.

It is another object of the invention to provide a spinning method and an apparatus therefor which make it possible to produce the excellent spun yarn made of short staples.

To achieve the above-mentioned object, in accordance with the invention, the exit end of the staple inlet guide tube is positioned close to and opposite the upper inner wall of the spinning rotor so that the long staples from the staple inlet guide tube are sucked to deposit on said upper inner wall, and, if desired, a few long staples not yet separated are fed from the staple inlet guide tube onto the upper inner wall of the spinning rotor so that the earlier and the later coming staples are separated from one another and, at the same time, de posited in turn onto the upper inner wall by virtue of the rotating air stream and the centrifugal force due to the high speed rotation of the spinning rotor and, furthermore, the conical inner wall portion of the spinning rotor rising from the collecting portion toward said upper inner wall is made steeper with respect to the horizontal plane passing through the collecting portion than it is in the prior art, whereby the staples sucked and deposited on said upper inner wall will gradually fall down to be collected to the collecting portion.

Also in accordance with the invention, there is pro' vided inside the spinning rotor a stationary cylindrical body which extends from a point near the top end of the spinning rotor to a point near the collecting portion. The clearance between the outer surface of this cylindrical body and the aforementioned conical inner wall increases from the top of the inner wall toward the collecting portion, so that the air stream and centrifugal force due to the rotation of the spinning rotor may be stabilized and increase gradually thus preventing the staples deposited on the inner wall from falling quickly or from coming off the inner wall and wafting in the space within the spinning rotor.

Attached to the bottom surface of the stationary cy lindrical body is a friction member whose end face is located below the extensional surface of the funnelshaped inner wall extending from the collecting portion of the spinning rotor, in order to give sufficient twist to the staples between the end face and the collecting portion to prevent breaking of yarn. More specifically, the staples between the collecting portion and the end face of the friction member are hard twisted toward the collecting portion with said end face as a fixed point as the staples are brought into contact with the funnel-shaped inner wall to promote the twisting. Accordingly, during this process the staples undergo not only a twisting applied at the rate of one turn per revolution of the spinning rotor but also a false twist-fashioned hard twisting, thus preventing perfectly the yarn breaking which is apt to occur during this period.

Further in accordance with the invention, there is provided in the central part of the stationary cylindrical body a yarn outlet guide tube whose entrance end is spaced from the end face of the friction member whereby at least a portion of excessive false twist given between the collecting portion and the end face for purpose of yarn breakage prevention may be cleared between the end face and the outlet guide tube. This control of the degree of twist is carried out by preparing many friction members of different shape for use to change the distance between the friction member and the collecting portion depending on yarns desired. Namely, decreasing the distance between the friction member and the collecting portion will cause increased twist of the staples or yarn therebetween, whereas increasing that distance will cause increased untwisting.

The features and other advantages of the invention will be clearly understood from the description of its embodiment illustrated in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a longitudinal cross section of an embodiment of the apparatus in accordance with the invention,

FIG. 2 is a picture for explaining preferable taper angles of the conical inner wall of the spinning rotor,

FIG. 3 is a picture for explaining the falling down of staples within the spinning rotor as well as the relative position of the funnel-shaped inner wall portion of the spinning rotor and the end face of the friction member,

FIG. 4 is a picture for explaining the relative position of the friction member and the yarn outlet guide tube,

FIG. 5 is a longitudinal cross section of another embodiment of the apparatus in accordance with the invention,

FIG. 6 is a picture showing a modification of the angle of the inner wall of the spinning rotor and showing the relative position of the upper inner wall and the staple inlet guide tube,

FIG. 7 is a picture showing spinning in a prior-art spinning rotor, and

F IG. 8 is a picture corresponding to the cross section taken through line V-V in FIG. 5 and showing a hitch of yarn in the collecting portion.

DETAILED DESCRIPTION Referring to FIG. 1, the spinning rotor l in accordance with the invention has a conical inner wall portion In extending upward from the collecting portion a. The slope of the conical inner wall portion In with respect to a plane perpendicular to the axis of the spinning rotor is fairly steeper than it is in the prior art spinning rotor. The funnel-shaped inner wall portion lb extending downward from the collecting portion has a taper angle such as to accelerate the twisting of staples by frictional contact. Inside the spinning rotor is provided a stationary cylindrical body 2 coaxial with the spinning rotor and extending from a point near its top end to a point near the collecting portion, for the purpose of stabilizing the air stream in the spinning rotor and preventing the scattering of separated staples to help them fall smoothly. A yarn outlet guide tube 3 is carried in the center of the cylindrical body, and one end of yarn inlet guide tube 4 is inserted in a bored portion at the top of the cylindrical body.

Another feature of the invention is that on that end face of the stationary cylindrical body 2 which lies in the spinning rotor is mounted on annular friction member 5 made of a material having a high frictional resistance such as hard rubber or plastics, and that the top 5a of this resistance member is positioned below the extensional plane L extending from the collecting portion a to the end b of the inner wall portion lb and there is a suitable clearance between the friction member and the yarn outlet guide tube 3. The friction member may have in its surface some suitable grooves for increasing frictional Contact with the yarn.

In the lower part of the spinning rotor there are provided dischargeholes 6 for making a negative pressure inside the spinning rotor, allowing the air in the spinning rotor to be sucked out through a suction tube 7 connected to a force sucking means such as a fan, not shown. Controlling this suction may change the velocity of staples in the inlet guide tube 4. The numeral 8 shows a sealed housing, 9 a pulley for rotating the spinning rotor, 10 a pair of yarn dragging rollers, 12 a wind ing roller, 13 a winding bobbin.

In FIG. 2 is shown the taper angle of the conical inner wall portion 1a in the spinning rotor. This angle is preferably with respect to a plane through the collecting portion of the rotor, for if the angle were for example, the staples sucked and deposited on the inner wall would not smoothly fall downward, because the centrifugal force of the rotor is large in comparison with the absorption force generated by the force suction means. Whereas if it were 60, the staples would not fall in a sliding fashion along the inner wall but would directly drop to the collecting portion.

FIG. 3 shows the relative position of the inner wall portion lb of the spinning rotor and the top portion 5a of the friction resistance member. In order to avoid arched drooping of staples or yarn between the collecting portion a and the top portion 5a so as to gain effective twist, the top 5a is located below an imaginary extensional plane L. The staples are given hard twist between the top 5a and the collecting portion with the top 50 as a fixed point and are untwisted in the downstream region of the top fixed point to have soft twist.

FIG. 4 shows the relative position of the friction member 5 mounted on the end face of the stationary cylindrical body 2 and the entrance part 30 of the yarn outlet guide tube 3. The distance I between the inner surface of the entrance portion 3a and the inner surface of the friction member 5 is large enough to increase the untwisting effectively. Therefore softer twist is gained at a position of friction member 5' shown in an imaginary line. On the other hand, at this position, the friction member is close to the collecting portion, so that harder twist will be given to the staples between the collecting portion and the friction member. By preparing various friction members and selectively setting one of them in a position suitable for the kind of staples to be used and yarn required.

FIG. 5 shows another embodiment of the invention. This embodiment is similar to that shown in FIG. I, the difference being that here one end of yarn inlet guide tube 4 is opposite a draft roller 14 while its other end is supported in the stationary cylindrical body 2 along its peripheral surface and especially the exit end 4b of yarn inlet guide tube 4 keeps a strictly predetermined distance to the upper inner wall 1a of the spinning rotor.

Like the embodiment in FIG. 1, the lower end of the stationary cylindrical body 2 extends as far as a position located in the same plane as the collecting or maximum inner diameter portion a of the spinning rotor, whereby to stabilize the air stream produced in the spinning rotor. The circumferential length of the cylindrical body is preferably made longer than the longest staple to be spun. To the underside end face of the stationary cylindrical body is attached an annular friction member 5 for applying adequate twist to yarn by means of its frictional resistance. One end of the staple inlet guide tube, that is, the staple introducing port 4a is opposite a pair of draft rollers 14 and the other end, i.e. staple outlet port 4b in opposite the upper inner wall la of the spinning rotor. It is to be understood that the other end of the staple inlet tube may be attached to the top end face of the stationary cylindrical body and a guide groove connecting to this other end may be formed in the inner surface of the cylindrical body. The symbol shows a safety pin for fixing the stationary cylindrical body 2 to housing 8 and 16 shows the machine base.

In the present apparatus, the upper inner wall In of the spinning rotor and the staple outlet end 4b of the staple inlet guide tube must be arranged with predetermined angle and distance, so that a few long staples not yet separated sucked from the inlet guide tube can be separated as they are drawn in turn from the staple outlet end 4b onto the upper inner la whereby the staples may be deposited along the peripheral inner surface of the upper inner wall in substantially parallel arrangement. To obtain good separation and depositing the clearance or distance between the outlet end 4b and the upper inner wall la is preferably less than 5m/m, according to the experiments made by the inventor, although it may differ according to the kind of staples fed and the suction produced in the spinning rotor.

By the air stream and centrifugal force due to rotating spinning rotor the staples arrived at the outlet port 4b can successively drawn to be separated, starting with their leading ends, and deposited almost parallel to each other and to a horizontal plane in the radial direction of the spinning rotor (FIGS. 1 and 3) on the inner wall. The staples so separated into individuals are then slide on the inner wall to go to the collecting portion of the spinning rotor.

To enable the transfer of separated staples along the inner wall surface, the inventor prepared, and made experiments on. spinning rotors having various taper angle of the inner wall. The result of the experiments was that the conical inner wall should have a taper angle of 7080 with respect to a plane passing through the collecting portion and be directed to the axis of the spinning rotor in order that the staples separated as mentioned above can gradually fall to the collecting portion in a gentle spiral as a whole while maintaining mutual parallelism. The length of the inner wall above the collecting portion is preferably 5-50 mm according to the length of staples to be used.

FIG. 6 shows another form of the inner wall of the spinning rotor in which only the upper inner wall la is tapered with an angle of 70-80 with respect to a plane perpendicular to the axis of the rotor, the other inner wall portions being tapered with suitable angles. The outlet end 4b of staple inlet guide tube 4' is positioned opposite said inner wall with a predetermined distance in between. Though with such positional relationship, it is possible to draw staples consecutively from the exit portion to separate them and to thus separated staples onto the inner wall, yet the transfer of staples to the collecting portion occurs rather early resulting in a overlap of staples at the collecting portion and therefore the embodiment in FIG. 2 is recommended.

FIG. 7 shows the way in which staples fall in the prior art spinning rotor. In the embodiment of FIG. 3, the parallel staples deposited on the surface of the upper inner wall la as individual staples gradually fall to the collecting portion spirally along the inner wall which is formed to gradually increase the centrifugal force, while in the one shown in FIG. 7, individual staples separated before hand is directly collected from the exit end of the staple inlet guide tube 4' to the maximum inner diameter portion, and for this reason, especially when fine count long staples are to be spun, the staple will endlessly stacked to the collecting portion and this will produce hitches as shown in FIG. 8 when the staples are drawn out, causing breaking of yam to the extent that continuous spinning becomes impossible.

In accordance with the apparatus and method of the invention, the separated staples will heap as parallel individuals in the direction to the collecting portion and the earlier arrived staples, being spun, and the later arrived staples will consecutively be combined and twisted near the collecting portion of the spinning rotor, so that yarn breakage due to hitches of yarn especially when using long staples can be avoided and continuous spinning becomes possible.

Now, the method in accordance with the invention will be described referring to FIG. 5.

In FIG. 1 opened long staples S opened as by opening roller are fed from the inlet guide tube 4 toward the upper inner wall la of the spinning rotor. The staple will then be sucked and deposited onto said inner wall la by the strong air stream and centrifugal force due to high speed rotating rotor, and slide down gradually to be collected at the collecting portion under the action of the successively increasing centrifugal force of the rotor. The collected staples is given a false twist and a twist between the inner wall lb and the top 50 of the friction resistance member 5.

ln starting period, a leader yarn is sucked into the spinning rotor through yarn outlet guide tube 3 by means of a force suction machine, and the end of the leader yarn is deposited near the collecting portion by the rotating air stream and centrifugal action of the rotor and made to contact the collected staples on the collecting portion so as to be twisted and spun.

As is well known, it is necessary to give a hard twist to the staples near the stripping point during spinning by the open end method. According to the method and apparatus of the invention, a friction member 5 is mounted on the lower end face of the stationary cylindrical body 2 at a suitable position between yarn outlet guide tube end 3a and the collecting portion of the spinning rotor l and the top 511 is located below the extensional plane L extending from the collecting portion a to the end b of the inner wall lb (see FIGS. 3 and 4). Consequently the yarn spun in the collecting portion a comes from the collecting portion a to contact slightly with the inner wall 1b as it is rotating about the yarn outlet guide tube end 3a and slidingly contact the top 5a of the friction body, then drawn out by drawing-out roller 11 through yarn outlet guide tube 3 and at least wound on a bobbin 13 by means of winding roller 12. When contacting and passing on the friction member, the yarn is rotated because of frictional resistance given to its surface thereby to produce a temporary twist.

This temporary twist is in the same direction as the twist given by the rotation of the spinning rotor on the collecting portions side of the top portion 5a of the friction member 5, and at least a portion of said temporary twist is cleared on the downstream side of the top portion. Therefore by adjusting it yarns having a desired degree of twist may be obtained. The degree of twist for the desired count of yarn may also be obtained by adjusting the velocity of rotation of the spinning rotor, the position of contact of the yarn with the top of the friction member (position measured from the yarn outlet guide tube end 30) and the depth of the grooves of the friction member.

The fact that the top portion a of the friction member 5 is located below the extensional plane L to make yarn contact the inner wall portion lb serves to prevent the space rotation of the yarn running from the collecting portion to the top portion 5a and prevent the yarn from getting arched due to air resistance (which may produce entrainment of twist in case of hard twist) to conduct twisting smoothly. Here the angle of the inner wall lb to the plane at spinning portion is preferably -50. In order to smoothly lead staples collected at the collecting portion toward the top 50 of the friction member, a number of spaced discharge holes in the periphery of the inner wall lb. The diameter of the discharge holes is preferably 1-1.5 mm. The holes may preferably be arranged in two parallel rows in the lower part of the collecting portion.

As seen from the foregoings, the invention permits efficient spinning while avoiding yarn breakage due to hitched staples since the separated staples consecutively slide down along the upper inner wall of the spinning rotor and then run downward in contact with the inner wall lb.

Yarns spun in accordance with the invention, especially those made of long staples, have good parallelism between staples and therefore good expandibility and strength. Spinning out of a fine count yarn using long staples as well as adjustment of twist are also possible.

in the embodiment shown in FIG. 5, a small number, preferably 5-10, of unseparated long staples S fed from a pair of draft rollers 14 situated above the spinning rotor are led to a entrance port 4a of a staple inlet guide tube 4 and drawn onto the upper inner wall la from exit port 4b by suction of a force sucking means. At that time the staples at the exit end 4b tend to fall by downward suction, but since the exit end 4b is opposite the upper inner wall and the distance therebetween is rather small, the staples are drawn to the upper inner wall of the spinning rotor by virtue of the rotational air stream caused around the circumference of the upper wall and the centrifugal force due to high speed rotation of the rotor. The velocity of transfer of the long staples flowing in the inlet guide tube 4 is 50l 50 m per minute while the speed of the spinning rotor is 3,000l0,000 m per minute and therefore a big velocity difference arises between the staples deposited on the inner wall and the following staples coming from the entrance 4a, which will produce a high speed draft and separation between the staples in the spinning rotor and the later coming staples. The staples so separated and deposited gradually descend along the tapered surface extending from the upper inner wall of the spinning rotor having 25-50 mm length and 7080 inclination to the maximum diameter portion having increased diameter where the centrifugal force is accordingly increased. In this process, air in the rotor is sucked through a discharge holes 6 formed in the lower part of the rotor by means of a force suction means, this downward suction serving to assist the staples fall.

The staples, which have gradually fallen and collected at the maximum diameter portion are then hard twisted to make a yarn between the inner wall portion lb extending toward the lower center of the spinning rotor and the friction member mounted on the lower end of the stationary cylindrical body, and then, while being untwisted, wound on a bobbin 13 by means of a winding roller 12 via the outlet tube 3 and a pair of guide rollers 11.

As seen from the above, especially in FIG. 5, it is possible to separate a few unseparated long staples into individual staples in the spinning rotor, whereby usual combing process may be omitted or shortened without any breakage of staples.

[t is also possible to make the separated staples as individuals fall along the inner wall to the collecting portion while maintaining parallel relation, whereby preventing hitch of staples, hence breaking of yarn, and enabling a smooth spinning of long staples, particularly, fine count long staples.

It is also an advantage that in this invention the diam eter of the collecting portion of the spinning rotor may less than 0.5 of the maximum length of staples to be used, while in the prior art spinning rotor, it must be 2-3 times the maximum length of staples.

Further, when compared with the spun yarn made of short staples produced by means of the known open end system, it has been ascertained the spun yarn produced from short staples by this invention is excellent in its strength and elasticity, and has few unevenness of yarn.

I claim:

1. In a method for spinning staples by the open-end system comprising collecting staples sucked from a staple inlet guide tube onto the inner wall of a spinning rotor, twisting said staples while stripping the same, and drawing said staples through a yarn outlet guide tube to a winding device, the improvement comprising: successively sucking a small number of unseparated long staples, fed in the form of a sliver, from a staple inlet guide tube, in the order of arrival from the exit end of said inlet guide tube so as to separate them from one another within the spinning rotor and causing said staples to deposit substantially parallel to each other and to a horizontal plane in the radial direction of the spinning rotor on the circumferential surface of the upper inner wall thereof, the separation of the small number of unseparated long staples being carried out in the narrow clearance between the exit end of the staple inlet guide tube and the upper inner wall by means of the rotating air stream and centrifugal force due to the rotating spinning rotor, causing the deposited staples to slide down toward the maximum diameter portion of the spinning rotor by means of a downward suction force while maintaining said staples parallel, in a gentle spiral as a whole, and thereafter giving said staples collected at the maximum diameter portion a false twist in the region between said portion and the vicinity of the entrance of the yarn outlet guide tube so as to prevent the yarn from breaking. 

1. In a method for spinning staples by the open-end system comprising collecting staples sucked from a staple inlet guide tube onto the inner wall of a spinning rotor, twisting said staples while stripping the same, and drawing said staples through a yarn outlet guide tube to a winding device, the improvement comprising: successively sucking a small number of unseparated long staples, fed in the form of a sliver, from a staple inlet guide tube, in the order of arrival from the exit end of said inlet guide tube so as to separate them from one another within the spinning rotor and causing said staples to deposit substantially parallel to each other and to a horizontal plane in the radial direction of the spinning rotor on the circumferential surface of the upper inner wall thereof, the separation of the small number of unseparated long staples being carried out in the narrow clearance between the exit end of the staple inlet guide tube and the upper inner wall by means of the rotating air stream and centrifugal force due to the rotating spinning rotor, causing the deposited staples to slide down toward the maximum diameter portion of the spinning rotor by means of a downward suction force while maintaining said staples parallel, in a gentle spiral as a whole, and thereafter giving said staples collected at the maximum diameter portion a false twist in the region between said portion and the vicinity of the entrance of the yarn outlet guide tube so as to prevent the yarn from breaking. 